| 摘要 |
PROBLEM TO BE SOLVED: To control the quantity of transfer charge to be applied to recording material to optimum one and to maintain excellent transfer performance by controlling transfer bias impressed on transfer material based on heating control to a heating member. SOLUTION: In this fixing device 6, the temperature of a heater 12 is controlled according to the number of passing recording material P, that is, what is called number-of-passing paper control is performed. When a printing signal is inputted and printing action is started from the stopping state of the image forming device, the temperature of the heater 12 before performing the action is detected by a temperature detection sensor 14. The control temperature is decided according to a table from the detected temperature. When the previously set number of passing recording paper is attained, controlled temperature is switched. The controlled temperature of the heater 12 has relation to the temperature of a pressure roller 13. In relation between the temperature and the outside diameter of the roller 13; the outside diameter of the roller 13 is estimated from the controlled temperature, substantially, the detected temperature and the number of passing recording material P. Then, a correction value according to the detected temperature is added to transfer bias and impressed on a transfer roller 5. |
